Clarification on Memory Allocation in nRF52805

[Tanuja Gudaje]

Hi Team,

I am currently working on the nRF52805 module and have developed an application that supports dynamic service creation (runtime GATT service creation).

During compilation, I observed that the RAM usage is already around 95%, which leaves very little space for additional application features and may lead to stack overflow in future updates.

Therefore, I would like to understand how the memory is currently allocated in the system. Specifically, I would like clarification on:

• How much RAM is reserved for the BLE stack

• How much RAM is used by the application

• How the overall memory configuration is distributed between the stack and application

This information will help us evaluate the remaining memory availability and plan further application development accordingly.

Regards,
Tanuja

[SwRa]

Hi Tanuja,

There is no single fixed value for BLE stack RAM in nRF Connect SDK. In nRF Connect SDK, the BLE stack is modular and configurable via Kconfig options in prj.conf. Only the features you explicitly enable are compiled in and consume RAM/Flash. The actual RAM consumed depends heavily on which BLE roles are enabled (broadcaster, peripheral, central, observer), number of connections (CONFIG_BT_MAX_CONN), buffer sizes, features like SMP, GATT caching, PHY update, etc.

The best way to understand your current allocation is to use the Memory Report feature in nRF Connect for VS Code. It provides a sunburst chart showing RAM and ROM usage broken down by SDK folder, source file, and symbol as well as separate tabs for ROM and RAM. See here: https://docs.nordicsemi.com/bundle/nrf-connect-vscode/page/reference/ui_memory_report.html#interactive-memory-report 

I would also suggest that you refer the memory optimization guide here:  Memory Optimization with the nRF Connect SDK  

Best Regards,

Swathy

[Tanuja Gudaje]

Hi Swathy,

Thank you for the clarification.

I understand that the BLE stack RAM usage in nRF Connect SDK depends on the enabled features and Kconfig configuration. I will review the Memory Report in VS Code to analyze the current RAM allocation and refer to the memory optimization guide as suggested.

Thanks for sharing the documentation links.

Best regards,
Tanuja